Pipe outer surface inspection apparatus

ABSTRACT

A pipe outer surface inspection apparatus. The apparatus may include a carriage adapted for turning on a pipe to be inspected and includes a pipe inspection head. The apparatus may include at least one of a surface profile gauge, coating thickness gauge, and coating holiday detector. The apparatus may include a pendulum encoder, a cable guard, and/or a magnetic fastener. Associated methods are also disclosed.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Patent ApplicationNo. 61/793,458, filed Mar. 15, 2013, which is hereby incorporated byreference in its entirety.

FIELD OF THE INVENTION

The present disclosure generally relates to inspection of pipes, andmore particularly to an apparatus for inspecting an outer surface of apipe for conditions such as proper surface preparation prior to coatingand/or proper coating application.

BACKGROUND OF THE INVENTION

Pipes of hazardous material conveying pipelines and other types ofpipelines may be coated to protect the pipes from corrosion and increasetheir lifespan. Inspection of aspects of the pipe after it is preparedfor coating and after the coating is applied ensures that desiredcoating specifications are met and the benefits of coating are realized.For example, a pipe may be prepared for coating by blasting to create asurface to which the coating can bond. The pipe may be inspected afterthis preparation step to determine if an adequate anchor profile for thecoating was achieved by the blasting. After coating is performed, thecoating may be inspected for discontinuities and/or desired thickness.Inspection of these aspects is particularly relevant in field coating,such as field coating of pipeline joints.

SUMMARY

One aspect of the present invention is directed to a pipe inspectionapparatus including a carriage adapted for turning on a pipe to beinspected and including a pipe inspection head.

Another aspect of the present invention is directed to an automated pipeinspection apparatus including at least one of a surface profile gauge,coating thickness gauge, and coating holiday detector.

Another aspect of the present invention is directed to a pipe inspectionapparatus including a pendulum encoder.

Another aspect of the present invention is directed to a pipe inspectionapparatus including a cable guard.

Yet another aspect of the present invention is directed to a pipeinspection apparatus including a magnetic fastener for securing aportion of the apparatus on the pipe.

Other objects and features of the present invention will be in partapparent and in part pointed out herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective of a pipe inspection apparatus according to thepresent invention mounted on a pipe section;

FIG. 2 is a view of the apparatus similar to FIG. 1 but having shroudsremoved to expose interior components;

FIG. 3 is a front perspective of a base of the apparatus;

FIG. 4 is a rear elevation of the apparatus having a rear base framemember removed to expose a magnetic fastener engaged with the pipe forsecuring the base on the pipe section;

FIG. 5 is a view similar to FIG. 4 but showing the magnetic fastenerdisengaged from the pipe;

FIG. 6 is a front perspective of a carriage of the apparatus;

FIG. 7 is a left side elevation of the apparatus mounted on the pipesection;

FIG. 8 is a top view of the apparatus and pipe section;

FIG. 9 is a right side view of the apparatus and pipe section;

FIG. 10 is a front elevation of the apparatus and pipe section, thecarriage being shown in a home position with respect to the base;

FIG. 11 is a view similar to FIG. 10 but showing the carriage rotated ina counterclockwise direction with respect to its home position; and

FIG. 12 is a view similar to FIG. 10 but showing the carriage rotated ina clockwise direction with respect to its home position.

Corresponding reference characters indicate corresponding partsthroughout the drawings.

DETAILED DESCRIPTION

Referring to FIGS. 1 and 2, an outer pipe surface inspection apparatusaccording to the present invention is designated generally by thereference number 10. As will become apparent, the apparatus 10 isadapted for automated inspection of various aspects of an outer surfaceof a pipe. The apparatus 10 is modular for carrying inspection heads ofvarious types. The apparatus 10 is configured for inspecting the fullcircumference of a pipe section. For example, the apparatus 10 may beused to inspect an anchor profile of the pipe surface after the pipe hasbeen blasted in preparation for coating the pipe. The apparatus 10 maybe used to inspect coating applied to the pipe for coating thicknessand/or coating irregularities known as holidays. The apparatus 10 isparticularly suited for inspecting the area of a pipe joint (e.g., awelded joint) for anchor profile and coating properties achieved whilefield coating the pipe joint. In FIG. 1, the apparatus 10 is shownmounted on a pipe section P including a joint J.

The apparatus 10 generally includes a stationary base 12 adapted forsecurely engaging the pipe P and a carriage 14 mounted on the base formovement with respect to the base to turn back and forth around the pipe(e.g., see FIGS. 10-12). The carriage 14 turns around the pipe in afirst direction (e.g., clockwise) and then a second direction (e.g.,counterclockwise) to permit inspection of an entire circumference or atleast a portion of the circumference of the pipe. As described infurther detail below, the base 12 includes control components, aportable power source, various inspection gauges, and drive componentsfor driving revolving motion of the carriage 14. The carriage 14includes various inspection components used to inspect the outer surfaceof the pipe. In the view of FIG. 1, the base 12 is positioned behind orto the left of the carriage 14. The base 12 and carriage 14 are shown bythemselves in FIGS. 3 and 6, respectively, and will be described infurther detail below.

As shown in FIG. 1, the base 12 includes a shroud 20 for covering avariety of control and drive components. In FIG. 2, and in the majorityof the remainder of the figures, the shroud 20 is removed for exposinginterior components. A handle 22 is provided on top of the shroud 20 forassisting a user in carrying the apparatus 10 between inspection sitesand in positioning the apparatus on a pipe section P to be inspected. Aswill become apparent, the apparatus 10 is configured to be mounted onthe pipe by being set onto the pipe from a position above the pipe. Theapparatus 10 may be removed from the pipe by raising it generallyvertically off the pipe. To inspect several sections of the same pipe,the apparatus 10 is carried to and mounted on the separate sections ofthe pipe. After being mounted on a pipe section, the apparatus 10 mayinspect the outer surface of the pipe at that section automatically,semi-automatically, or under substantial manual direction.

The apparatus 10 includes control actuators 24 such as buttons orswitches positioned on an upper side of the shroud 20. The actuators 24may be operative to power the apparatus 10 on/off, select betweenautomatic and manual modes, and/or initiate an inspection step. Theapparatus 10 may include a mobile computing device 26 (e.g., smartphone, tablet, or portable computer). In the illustrated embodiment, thedevice 26 is received in a mount on the shroud 20 for releasablysecuring the device on the base 12. The device 26 may include amicroprocessor, data storage media, user data input interface (e.g.,keypad or touch screen), communications interfaces (e.g., wiredconnection ports, wireless antennas, and modems), and/or GPS antenna.Data acquired, received, stored and/or processed by the mobile computingdevice 26 may be used in conjunction with inspection data collected byother devices on the base 12 and devices carried on the carriage 14. Forexample, the mobile computing device 26 may be used as a controller forreceiving and executing inspection instructions and for collecting andlogging inspection data from various inspection components of theapparatus 10.

Referring now to FIG. 3, the base 12 includes a generally saddle-shapedframe 30 sized and shaped for straddling the pipe section P. The frame30 includes a rear semi-circular frame member 30A and a front U-shapedframe member 30B providing the base with a mouth opening in a downwarddirection for being received over the pipe. The frame members 30A, 30Bare connected to each other by a plurality of rungs 30C. Both of theframe members 30A, 30B include feet 32 protruding radially inward forengaging the pipe and supporting the base 12 on the pipe.

The base 12 includes a magnetic fastener 36 adapted for selectivelysecuring the base in position on the pipe P. The fastener 36 includes alever 38 pivotally connected to the frame 30 for engaging anddisengaging a pair of ferromagnetic feet or magnets 40 with the outersurface of the pipe. When engaged with the pipe, the magnets 40 providethe equivalent of about 80 to 100 pounds of force acting to maintain thebase 12 in position on the pipe. The magnets 40 are actuated byrespective front and rear arms 42 of the lever 38. The fastener 36 isshown in closer detail in the views of FIGS. 4 and 5 in which the rearframe member 30A is removed to expose the rear side of the fastener. Thefastener 36 is shown in a fastening position in FIG. 4 in which themagnets 40 are engaged with the pipe, and the fastener is shown in anon-fastening position in FIG. 5 in which the magnets are disengagedfrom the pipe. The fastener 36 includes an over-center pivot arrangementadjacent the proximal end of the lever 38 for moving the magnets 40toward and away from the pipe. The arms 42 are connected to respectivelegs 44 and pivot bars 46 by non-fixed pivot connections 48, 50. Thepivot bars 46 and feet are pivotally connected to respective framemembers 30A, 30B by fixed pivot connections 52, 54. The arrangement issuch that movement of the lever 38 tending to move its distal endradially away from the pipe causes the magnets 40 to disengage the pipe.The pivot connection 48 of the arm 42 and the leg 44 passes “overcenter” between the fixed pivot connections 52, 54 of the leg and pivotbar 46 to the frame 30, and in the “over center” position the magnets 40are held by the linkage against the force of gravity and magneticattraction away from the pipe. Accordingly, the base 12 may beselectively fastened to and unfastened from the pipe by actuating thelever 38 to engage and disengage the magnets 40 from the pipe. Thesecure connection of the base 12 to the pipe provides a stable platformfor supporting the carriage 14 while it revolves around the pipe. Othermeans of securing the base 12 to the pipe may be used without departingfrom the scope of the present invention. For example, a strap may beconnected to and tightened between opposite sides of the U-shaped framemember 30B below the pipe.

Various control and inspection components are mounted on the base 12.These components are shown in FIG. 3, but may be better viewed in FIGS.7, 8, and/or 9. For example, the base 12 may include an integralcontroller 60 for use in conjunction with the mobile computing device 26and/or as a stand-alone controller. Like the mobile computing device 26,the controller 60 may include a microprocessor, data storage media,communications interfaces (e.g., wired connection ports, wirelessantennas, and modems), and/or GPS antenna. The controller 60 is inoperative communication with the actuators 24 (e.g., for receivinguser-input regarding start/stop and/or manual/automatic modes). The base12 includes a portable power source 62 (e.g., at least one battery) forpowering the various electronic components of the inspection apparatus10. The base 12 includes a holiday detection processor 64 incommunication with a device carried by the carriage 14 as part of anelectronic holiday detector, as explained in further detail below. Thebase 12 also includes an ambient condition gauge 66 and a pipetemperature gauge 68. The ambient condition gauge 66 may be adapted forsensing the ambient temperature and/or humidity adjacent the pipe. Thepipe temperature gauge 68 is adapted for sensing the surface temperatureof the pipe. As shown in FIG. 9, the pipe temperature gauge 68 includesa temperature probe 68A and an actuator 68B (e.g., a solenoid) forextending and retracting the probe radially with respect to the pipe forsensing its surface temperature and storing the probe in a retractedposition. The holiday detection signal processor 64, ambient conditiongauge 66, and pipe surface temperature gauge 68 are in operativecommunication with the controller 60 and/or mobile computing device 26for transmitting signals representative of inspected characteristics forstorage, transmission offsite, and/or analysis.

Referring again to FIG. 3, a plurality of bearings 70 protrude from thefront face of the front U-shaped frame member 30B and collectivelydefine a track along which the carriage 14 is movable for revolvingaround the pipe P. The bearings 70 each have a generally cylindricalouter surface including a circumferential groove spaced between frontand rear ends of the bearings. The grooves of the bearings 70collectively define a semi-circular segmented channel for receiving thecarriage 14 and guiding rotation of the carriage. The bearings 70 maycomprise lubricant-impregnated metal for facilitating the carriage 14 ingliding along the bearings. Alternatively, the bearings may compriserollers. Other bearings may be used without departing from the scope ofthe present invention.

The base 12 includes a carriage drive system 74 for turning the carriage14 back and forth on the pipe (e.g., see also FIGS. 10-12). Referring toFIG. 3, in the illustrated embodiment, the drive system 74 includes amotor 76, a gear box 78, and a chain and sprocket assembly. The motor 76drives a primary sprocket 80 via the gear box 78, which in turn rotatessecondary sprockets 82 via a loop of chain 84 meshed with the threesprockets. The chain 84 is represented schematically in FIG. 3. Thesecondary sprockets 82 are connected to carriage drive sprockets 88 byrespective shafts passing through ears extending from the front framemember 30B. The drive sprockets 88 are positioned in the same plane asthe channel defined by the bearings 70. When the motor 76 is energized,the chain and sprocket assembly causes rotation of the carriage drivesprockets 88, which engage and drive the carriage 14 along the bearings70 about the circumference of the pipe. Other types and configurationsof carriage drive systems may be used without departing from the scopeof the present invention. For example, a geared system may be used, anda direct drive system may be used instead of an indirect drive system.

Referring to FIG. 6, the carriage 14 includes a semi-circular frame 90providing the carriage with a mouth facing downward for being receivedover the pipe. The frame 90 includes three C-shaped frame membersincluding a front frame member 90A, a rear frame member 90B, and anintermediate frame member 90C sandwiched by the front and rear framemembers. The inner edge of the intermediate frame member 90C extendsradially inboard of the inner edges of the front and rear frame members90A, 90B, providing the frame 90 with a radially inward protruding rib92. The rib 92 is sized and shaped for reception in the segmentedsemi-circular channel formed by the bearings 70 of the base 12. The rib92 serves as a guide for guiding the carriage frame 90 along the channeland maintaining it on the base 12. The outer edges of the front and rearframe members 90A, 90B extend radially outboard of the outer edge of theintermediate frame member 90C, providing the frame with a radiallyoutward facing channel 94. A length of chain 96 (broadly “drive systemengaging member”) represented schematically in FIG. 6 is received in thechannel 94. The chain 96 is adapted for engagement with the carriagedrive sprockets 88 on the base 12. Rotation of the carriage drivesprockets 88 causes the carriage frame 90 to move along the bearings 70,as described in further detail below. Other drive system engagingmembers may be provided on the carriage 14 without departing from thepresent invention. For example, instead of the chain 96, the frame 90may include a plurality of teeth resembling a geared surface. Moreover,the drive system engaging member may comprise a smooth or knurledsurface for frictional engagement with drive rollers of the carriagedrive system.

The carriage frame 90 includes inspection head mounting portions onopposing sides of the frame. In the illustrated embodiment, twoinspection heads 100, 102 are mounted on the opposing sides of the frame90, and a third inspection head 104 is mounted on an intermediateportion of the frame. The first and second inspection heads 100, 102 aremounted at positions generally diametrically opposed from one another.Such an arrangement improves balance of the carriage 14. In use, theseinspection heads 100, 102 would be positioned on opposing sides of thepipe P and promote balanced turning of the carriage 14 on the pipe. Thecarriage 14 is modular in that one or more of a variety of inspectionheads may be mounted on the frame 90 for turning on the pipe. It will beunderstood that although three inspection heads 100, 102, 104 are shown,given the modular nature of the apparatus 10, one or more (e.g., four,five, etc.) inspection heads may be mounted on the carriage frame 90 atany given time depending on the inspection tasks desired to becompleted. For example, if the apparatus 10 is being used to inspectsurface profile prior to coating, a single surface profile inspectionhead 100 may be used. On the other hand, if the apparatus 10 is beingused to inspect a coating for thickness and holidays, a coatingthickness inspection head 100 and a holiday inspection head 102 may bothbe mounted on the carrier frame 90. In either scenario, a camerainspection head 104 may be mounted on the carrier frame 90 forcollecting video or still photo image data representative of the areainspected. The camera inspection head 104 includes a support arm 104Aand a camera 104B positioned for viewing at least the circumferentialsection of the pipe over which the other inspection heads 100, 102travel. The camera 104B may include a fisheye lens to provide a widerfield of view. Some inspection processes are complemented by visualinspection to visually identify characteristics such as colorirregularity (e.g., rust) or burs. Image data from the camera 104B canbe logged and correlated with other inspection data to permit remote orlater visual inspection of areas identified as being problematic byother inspection heads 100, 102.

The apparatus 10 as shown in FIG. 2 is configured for inspecting a pipecoating for thickness and holidays. The first inspection head 100 may beadapted for inspecting coating thickness. A shroud 110 of the inspectionhead is shown in FIG. 1 but is removed in the majority of the otherfigures, including FIG. 2, to show internal components. Referring againto FIG. 6, the inspection head 100 includes an elongate shelf 112extending from a first end connected to the carriage frame 90 to anopposite end including a ferromagnetic wheel 114. The ferromagneticwheel 114 is magnetically attracted to the pipe and thus improves thestability of the shelf 112 by supporting the distal end of the otherwisecantilevered shelf in position with respect to the pipe. The wheel 114permits the shelf 112 to have a length sized to span a significantsection of the pipe yet maintain stability even when the carriage 14 ismoving quickly. The wheel 114 is rotatably mounted to the shelf 112 forrolling along the surface of the pipe as the carriage 14 moves. Anelectronic coating thickness gauge 116 is mounted on the shelf 112. Thecoating thickness gauge 116 includes a probe 116A supported below theshelf 112 on an actuator 116B (e.g., a solenoid) adapted for moving theprobe radially with respect to the pipe. For example, the probe 116A maybe adapted for induction, magnetic, or Hall effect testing to determinecoating thickness. The radial actuator 116B moves the probe 116A near orinto engagement with the surface of the pipe when turning of thecarriage 14 is paused. The coating thickness gauge 116 includes aprocessor 116C supported above the shelf 112 for processing signals fromthe probe 116A. Processed signals representative of coating thicknessare transmitted to the controller 60 or mobile computing device 26. Thecoating thickness gauge 116 also includes an axial actuator 116D adaptedfor moving the probe 116A axially with respect to the pipe. Accordingly,the probe 116A may measure coating thickness at various axial positionsalong the pipe as well as at different circumferential portions of thepipe. For example, the probe 116A is shown in FIG. 7 positioned to aright side of the joint J. The axial actuator 116D may be used to movethe probe 116A closer to the joint J and/or to the other side of thejoint. The controller 60 may be programmed to sample the coatingthickness at standard positions (e.g., radial positions corresponding to12, 3, 6, and 9 o'clock) and/or random positions. This increases theinspection thoroughness and reliability compared to manual execution ofthe inspection. For example, if coating thickness is determined by thegauge 116 to be out of specification in a certain area or almost out ofspecification, the frequency or density of testing in that area may beautomatically increased to assist in determining the extent of theproblem.

The first inspection head 100 also includes a radial position indicatingdevice 120 for indicating the radial position of the inspection head 100with respect to the pipe P. In the illustrated embodiment, the device120 includes a pendulum 120A operatively connected to an encoder 120B.The pendulum 120A is best viewed in FIGS. 7 and 8. The pendulum 120Apivots with respect to the encoder 120B as the carriage 14 rotatesaround the pipe so that the pendulum consistently hangs in a generallydownward orientation. The encoder 120B documents the angular position ofthe pendulum 120A to determine radial position with respect to the pipe.This information is transmitted to and may be logged by the controller60 and/or mobile computing device 26. Correlating the radial positioninformation with inspection data gathered, for example, from the coatingthickness probe 116A, in combination with GPS position information maybe used to relatively precisely pinpoint the location on the pipe whereinspection data (e.g., indicating a problem or need for furtherinspection) was acquired. The encoder 120B may be used for determiningradial position of any inspection component (e.g., of other inspectionheads) mounted on the carriage 14 and for correlating data collected bythose components to specific radial positions on the pipe assuming aposition of the inspection component is known with respect to theencoder. Other types of radial position indicating devices may be usedwithout departing from the scope of the present invention. For example,an accelerometer or an encoder operatively connected to the motor may beused.

Referring again to FIG. 6, the second inspection head 102 is adapted forinspecting pipe coating for holidays. Holidays are discontinuities inthe coating such as small holes or other irregularities providing apassageway to the pipe surface. The inspection head 102 includes anon-conductive insulator 130 in the shape of a bar extending from afirst end connected to the carriage frame 90 to an opposite endincluding a ferromagnetic wheel 132. The ferromagnetic wheel 132operates in the same fashion and provides the same benefits describedabove with respect to the first inspection head 100. In this case, theferromagnetic wheel 132 is particularly useful because inspection datais collected while the carriage 14 is moving, making stability ofinspection head 102 during movement even more relevant. A conductivetongue 134 extends along the length of the insulator 130 and protrudesinto engagement with the pipe coating. As the carriage 14 rotates, thetongue 134 wipes along the circumference of the pipe. The tongue 134 maycomprise a continuous flap or a brush including materials such asneoprene rubber, copper, stainless steel, or nylon. The tongue 134 has alength sufficient to engage the pipe across a span including the pipejoint J and end margins of the joined pipes on opposite sides of thejoint. The tongue 134 desirably conforms to a raised or otherwiseirregular profile of the joint J for detecting holidays not only on thesurfaces of the joined pipes but also at the joint. The radial positionof the tongue 134 with respect to the pipe surface can be adjusted bychanging the mounting points of the wheel 132 and carriage frame 90 onthe insulator 130. The tongue 134 is in operative communication with theholiday detection processor 64 on the base 12. A ground wire may extendfrom the processor 64 to ground such that changes in current field maybe detected. Current from the tongue 134 seeks a pathway to the pipesurface, but the coating acts as an insulator. Defects in the coatingprovide a pathway for the electrical current to “burn through” to thepipe and indicate to the presence of the defects to the processor. Likewith the coating thickness gauge 116, inspection data from theelectronic holiday detector is delivered to the controller 60 and/ormobile computing device 26 for transmission, logging, and/or analysis.The encoder 120B may be used to indicate circumferential positioning ofdetected holidays.

The first inspection head 100 may alternatively be described as beingadapted for inspecting a blasted surface profile or anchor profile ofthe pipe prior to coating. The configuration described above of head 100would be substantially the same in this case except that the gauge 116includes a probe 116A adapted for measuring the thickness of coating onthe pipe surface. In this case, the probe 116A may include a pin oranvil adapted for engaging the pipe surface for measuring “peaks” and“valleys” to determine the surface profile of the pipe. The radialactuator 116B moves the probe into engagement with the surface of thepipe when turning of the carriage 14 is paused. The actuators 116B, 116Dmay be used in a similar fashion as described above for sampling thesurface profile at various positions along the pipe section. If thesurface profile is determined by the gauge 116 to be out ofspecification or almost out of specification in a certain area, thefrequency or density of testing in that area may be automaticallyincreased to assist in determining the extent of the problem.

Referring again to FIG. 6, the carriage 14 includes a cable guard 140adapted for protecting cables 142 (shown schematically in FIG. 6) whichmay connect components of the base 12 with components of the carriage.For example, gauges 116 on the carriage 14 may require wired power to besupplied to the actuators 116B, 116D or the probes 116A. Moreover, acable extending from the base 12 to the tongue 134 of the holidaydetector may be required for supplying electrical current to the tongue.The cable guard 140 is a snake-like member which is flexible at least inthe plane in which the carrier revolves around the pipe. A proximal endof the cable guard 140 is connected to a front side of the shroud 20 ofthe base 12 (see FIG. 1). A distal end of the cable guard 140 ispositioned radially inboard from the first end and connected to thecarrier frame 90 adjacent the first inspection head 100. Cables 142 fromthe cable guard 140 leading to the first inspection head 100 exit thecable guard near the first inspection head. Cables 142 from the cableguard 140 leading to the second inspection head 102 exit the cable guardat about the same position as the other cables, but then extend alongthe carriage frame 90 to the second inspection head. The ends of thecable guard 140 may be pivotally connected to the base 12 and carriage14. The cable guard 140 may include generally rigid segments connectedto each other for pivoting movement in the plane in which the carriage14 revolves but for preventing substantial pivoting movement in adirection laterally with respect to the plane. Alternatively, the cableguard 140 may comprise a generally flexible material, such as a piece offlexible conduit or channel. The cable guard 140 may be tubular orchannel-shaped. In the illustrated embodiment, the cable guard 140 isshown schematically as a continuous channel.

The cable guard 140 is adapted for changing its configuration (e.g.,overlap or amount of fold) corresponding to movement of the carriage 14.The length of the cable guard 140 between its connection points to thebase 12 and carriage 14 is free of fixed connection and is thus free tochange orientation. A cable guard support 150 in the form of asemi-circular shelf protrudes from the front surface of the carrierframe 90. The cable guard 140 may engage or disengage this support 150depending on the rotational position of the carriage 14. In FIGS. 1, 2,and 10, the carriage 14 is shown in a “home” position with respect tothe base 12. In this position, the mouths of the base and carriageframes 30, 90 are in register with each other for receiving the base 12and carriage 14 over the pipe section. In the home position, a distalportion of the cable guard 140 is supported on the cable guard support150, and an intermediate portion of the cable guard overlaps itself,defining a fold where it turns from a first circumferential direction toan opposite circumferential direction with respect to the pipe. To movethe inspection heads 100, 102, 104 mounted on the carriage frame 90 asufficient amount to inspect the entire circumference of the pipesection, the carriage 14 needs to be adapted for turning a cumulativetotal of at least 360 degrees from the home position. In the illustratedembodiment, the cable guard 140 is sized for permitting the carriage 14to rotate in a clockwise direction (see FIG. 12) and a counterclockwisedirection (see FIG. 11) from the home position more than about 180degrees each direction (e.g., about 190 to 200 degrees each direction).The cable guard 140 may permit less of an extent of rotation (e.g.,non-overlapping) without departing from the scope of the presentinvention. However, it is desirable that at least a slight overlap inthe range of movement of the inspection heads 100, 102, 104 be providedto cover the entire circumference of the pipe. The controller 26, 60 maycontrol rotation reversal based on signals from the encoder 120B. Itwill be appreciated that the carriage 14 has a length sufficient to spanthe lower gap in the semi-circular channel formed by the bearings 70 andto remain in engagement with at least one carriage drive sprocket 88 atall times. As shown in FIG. 11, when the carriage 14 rotates in a firstcircumferential direction around the pipe P (e.g., counterclockwise),the overlap of the cable guard 140 tends to decrease, and the fold inthe cable guard may unfold. As shown in FIG. 12, when the carriage 14rotates in an opposite circumferential direction around the pipe (e.g.,clockwise), the overlap tends to increase initially, and the fold ismaintained. Moreover, the distal end of the cable guard 140 tends todisengage the cable guard support 150 and may completely disengage it.The configuration is such that the cable guard 140 and cable guardsupport 150 protect the cables 142 from interfering with the carriagedrive system 74 or being pinched, kinked, or severed during movement ofthe carriage 14.

As is now apparent, in use, an operator mounts desired inspection heads100, 102, 104 on the carriage 14, mounts the apparatus 10 on a pipesection P, and initiates inspection of the pipe section. The carriage 14turns back and forth on the pipe section to collect data suchrepresentative of surface profile, coating thickness, or coating voids.Visual data such as video and/or still photography may also becollected. Temperature of the pipe and ambient humidity and temperaturemay be determined All of the collected data may be logged, transmitted,and/or analyzed, such as by the mobile computing device 26, for readilydetermining deviations from required specifications more accurately andmore reliably than previously possible. When inspection of a pipesection is complete, the user may carry the apparatus 10 to another pipesection and repeat the inspection process.

It will be appreciated that the modularity and automation orsemi-automation of the inspection tasks accomplished by the apparatus 10provides multiple benefits over conventional inspection methods.Inspection consistency and thoroughness is improved, and inspection maybe more reliable than a person manually attempting inspection. Forexample, a person is less likely to sample various circumferentialpositions of a pipe when difficult to reach (e.g., the underside of thepipe, or the far side of the pipe). The apparatus 10 permits automatedlogging of various types of inspection data and correlation of thatdata. For example, temperature (pipe and/or ambient), humidity, surfaceprofile, coating thickness, coating discontinuity, and photographic orvideo inspection data may be gathered all by the apparatus 10 moreprecisely than previously possible and in a form in which problem areasand trends can be readily identified based on precise positioninformation (e.g., GPS position and radial position on the pipe sectioninspected). The position information may be used to map collectedinspection data and to authenticate inspection performance. Thesecapabilities of the apparatus 10 will provide pipeline owners withincreased assurance that coating preparation and application wereperformed to specification and will ultimately increase the lifespan ofpipelines because they will be better coated as a result of betterinspection.

Having described the invention in detail, it will be apparent thatmodifications and variations are possible without departing from thescope of the invention defined in the appended claims.

As various changes could be made in the above constructions and methodswithout departing from the scope of the invention, it is intended thatall matter contained in the above description and shown in theaccompanying drawings shall be interpreted as illustrative and not in alimiting sense.

1-5. (canceled)
 6. An outer pipe surface inspection apparatuscomprising: a base configured for mounting on the outer surface of thepipe; a carriage mounted on the base and configured to move with respectto the base generally along the circumference of the pipe; a carriagedrive system connected to the carriage and configured to drive movementof the carriage on the base; a coating thickness inspection head mountedon the carriage configured to inspect a thickness of a coating on theouter pipe surface; a coating holiday inspection head mounted on thecarriage, the coating holiday inspection head including a conductivetongue configured to wipe along the outer pipe surface as the carriageturns on the pipe; a camera inspection head mounted on the carriage; aradial position sensor mounted on the carriage configured to senseradial position of the carriage with respect to the pipe; a controlleroperatively connected to the carriage drive system, the coatingthickness inspection head, the coating holiday inspection head, thecamera inspection head, and the radial position sensor, the controllerbeing programmed to control turning of the carriage on the pipe andcontrol operation of the inspection heads.
 7. An outer pipe surfaceinspection apparatus as set forth in claim 6 wherein the controller isprogrammed to correlate radial position data from the radial positionsensor with inspection data from the coating thickness inspection head,the coating holiday inspection head, and the camera inspection head. 8.An outer pipe surface inspection apparatus as set forth in claim 6further comprising a pipe temperature gauge supported by the base andconfigured to measure the temperature of the pipe.
 9. An outer pipesurface inspection apparatus as set forth in claim 8 wherein the pipetemperature gauge includes a temperature probe and an actuatorconfigured to move the temperature probe radially with respect to thepipe.
 10. An outer pipe surface inspection apparatus as set forth inclaim 6 further comprising an ambient condition gauge supported by thebase, the ambient condition gauge including at least one of an ambienttemperature sensor and an ambient humidity sensor.
 11. An outer pipesurface inspection apparatus as set forth in claim 6 further comprisinga GPS sensor supported by the base.
 12. An outer pipe surface inspectionapparatus as set forth in claim 6 wherein the controller is programmedwith instructions to operate the carriage drive system to move thecoating thickness inspection head to locations spaced around acircumference of the outer pipe surface and to operate the coatingthickness inspection head to inspect coating thickness on the outer pipesurface at the locations.
 13. An outer pipe surface inspection apparatusas set forth in claim 12 wherein the controller is programmed withinstructions to, in response to detecting a coating thickness outside apredetermined specification, move the coating thickness inspection headto additional locations on the outer pipe surface and to operate thecoating thickness inspection head to inspect the outer pipe surface atthe additional locations.
 14. An outer pipe surface inspection apparatusas set forth in claim 6 wherein he controller comprises a mobilecomputing device and the outer pipe surface inspection apparatus furthercomprises a mount supported by the base configured to releasably mountthe mobile computing device on the outer pipe surface inspectionapparatus.
 15. An outer pipe surface inspection apparatus as set forthin claim 6 wherein the coating thickness inspection head includes aprobe adapted to measure the thickness of coating on the pipe surfaceand an axial actuator configured to move the probe axially with respectto the pipe.
 16. An outer pipe surface inspection apparatus as set forthin claim 6 wherein the coating thickness inspection head includes aferromagnetic wheel configured to engage and roll along the outer pipesurface.
 17. An outer pipe surface inspection apparatus as set forth inclaim 6 wherein the coating holiday inspection head includes aferromagnetic wheel configured to engage and roll along the outer pipesurface.
 18. An outer pipe surface inspection apparatus as set forth inclaim 6 wherein the radial position sensor includes an encoder.
 19. Anouter pipe surface inspection apparatus comprising: a base configuredfor mounting on the outer surface of the pipe; a carriage mounted on thebase and configured to move with respect to the base generally along acircumference of the pipe; a carriage drive system connected to thecarriage and configured to drive movement of the carriage on the base; asurface profile inspection head mounted on the carriage configured toinspect a surface profile of the outer pipe surface; a camera inspectionhead mounted on the carriage; a radial position sensor mounted on thecarriage configured to sense radial position of the carriage withrespect to the pipe; a controller operatively connected to the carriagedrive system, the surface profile inspection head, the camera inspectionhead, and the radial position sensor, the controller being programmed tocontrol movement of the carriage on the base and control operation ofthe inspection heads.
 20. An outer pipe surface inspection apparatus asset forth in claim 19 wherein the controller is programmed to correlateradial position data from the radial position sensor with inspectiondata from the surface profile inspection head and the camera inspectionhead.
 21. An outer pipe surface inspection apparatus as set forth inclaim 19 wherein the controller is programmed with instructions tooperate the carriage drive system to move the surface profile inspectionhead to locations spaced around a circumference of the outer pipesurface and to operate the surface profile inspection head to inspectsurface profile on the outer pipe surface at the locations.
 22. An outerpipe surface inspection apparatus as set forth in claim 21 wherein thecontroller is programmed with instructions to, in response to detectinga surface profile outside a predetermined specification, move thesurface profile inspection head to additional locations on the outerpipe surface and to operate the surface profile inspection head toinspect the outer pipe surface at the additional locations.
 23. An outerpipe surface inspection apparatus as set forth in claim 19 wherein thesurface profile inspection head includes a probe adapted to measure thesurface profile on the outer pipe surface and a actuator configured tomove the probe into engagement with the outer pipe surface.
 24. An outerpipe surface inspection apparatus as set forth in claim 19 wherein thesurface profile inspection head includes a ferromagnetic wheelconfigured to engage and roll along the outer pipe surface.
 25. An outerpipe surface inspection apparatus as set forth in claim 19 wherein theradial position sensor includes an encoder.